According to "High Explosives Propellants Pyrotechnics" by Ernst-Christian Koch, state of the art non-azide airbag comps are for example:
35 potassium perchlorate
50 Guanidinium nitrate
66.8 ammonium nitrate
6.7 potassium nitrate
21.5 diammonium 5,5'-bi-1H-tetrazolate
5.0 glass fibers (SiO2)
Both need strong confinement to burn quick, #3 is the fastest one.
Is liquid a possible solution and gas in the form of a mixture of steam and oxygen ok for your application?
Strong hydrogen peroxide (at least 40 % I think) dissociates very quickly into steam and oxygen when a small amount of potassium permanganate is added.